Havent run the 305 but I have a 304 ccr 07. It is a great machine. Dont know what year your looking at but they have changed a lot in the last few years from previous models. I chose the 304 for its ability and weight. At 10800lbs its light enough for me to move easily enough. Lots of other great brands out there, I like the cat because I deal with them on jobs and it make service and parts easily accessible. I would advise against any brand that parts and service were to far away or hard to reach. I really like my machine and its a total workhorse.
Dances with dirt- It's an 05. I didn't realize a 304 was that big. Not much difference in the 304 and 305 then. I'm kinda lookin for a little more reach and lifting ability. I run some bigger CATs and liked em but never a little one. I'm the same way as you, parts and service are a big deal to me. We have Cat, Bobcat, Kubota, and Komatsu pretty close